Balance sheet parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Assets
Available-for-sale investment securities at amortized cost	$ 602,817	$ 617,128
Held-to-maturity investment securities at Fair Value	$ 34,634	$ 16,705
Stockholders' Equity:
Preferred stock - Shares authorized	50,000,000	50,000,000
Preferred stock - Shares issued	0	0
Common stock - Shares authorized	24,000,000	24,000,000
Common stock - Shares issued	11,129,412	11,122,247
Treasury stock - shares	607,864	615,123